Progression of Oocyte Maturation From Metaphase I to Metaphase II is disturbed by previous immunological interference with cumulus cell function
✍ Scribed by Tesarik, Jan ;Lefèvre, Brigitte ;Testart, Jacques
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 913 KB
- Volume
- 260
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Abstract
The effects of an antibody preparation reacting with preovulatory mouse cumuli oophori (anticumulus Ig) on oocyte maturation in vivo and in vitro were studied. Continuous presence of anticumulus Ig in culture medium did not impair oocyte maturation in vitro. Similarly, no effect on oocyte maturation in vivo was observed when anticumulus Ig was given to females superovulated with pregnant mare serum gonadotopin (PMSG) and human chorionic gonadotropin (hCG) at the time of hCG treatment. However, when administered earlier, anticumulus Ig brought about serious disturbances of oocyte meiotic competence, since only immature oocytes were ovulated after anticumulus Ig injection at the time of PMSG treatment and as much as 70% of the ovulated oocytes were immature when the antibody was applied 24 hr later. Previous absorption of anticumulus Ig with isolated cumulus cells removed the inhibitory effect of this preparation on oocyte meiotic competence to the same extent as absorption with whole cumuli oophori, despite the persistence of a strong reactivity of the cumulus cell‐absorbed antibody preparations with the cumulus intercellular matrix. The ability of oocytes obtained from antibody‐injected animals to mature in vitro was also considerably impaired when the injection was made at the time of PMSG treatment. In all cases the maturation defect concerned the progression of meiosis from metaphase I to metaphase II, while the ability of oocytes to undergo germinal vesicle breakdown (GVBD) was unchanged. It is concluded that (1) the competence of oocytes to progress from metaphase I to metaphase II of meiosis can be subject to an isolated alteration without any disturbance of GVBD, (2) the cumulus cells sustain the development of the oocyte competence to effect the metaphase I–metaphase II transition, and (3) this activity of cumulus cells is limited in time and coincides with the PMSG action in the standard superovulation regimen.